Linguistic models have a fundamental weakness in the study of aphasia in that as models of a single linguistic competence they cannot in principle explain dissociations in language disturbances. Procedural (i.e., computational) models of specific language abilities/tasks are to be preferred in that they can explain dissociation data and they are necessarily very detailed to account for varied patterns of disrupted behavior. A procedural model of sentence production is outlined and the model is applied to account for some aspects of agrammatic speech.